Nato – chiefly Britain – appears to have toppled the Gaddafi regime in Libya to "liberate" its people. The days are over where the mere triumph of arms justifies itself. The rightness of a war and the honesty of its methods are vital if the new "liberal interventionism" is to carry its proclaimed moral clout. The Libyan operation is already being declared a classic success for the ideology. The following claims have been made for it over the past six months.

Intervention was necessary to prevent a massacre in Benghazi

There had been no massacre in Benghazi, only the threat of an attack on the city by Gaddafi if the rebels failed to negotiate. While the threat was real, the assumption of "thousands" of deaths was Nato propaganda to justify its desire to "do something" for the Arab spring. Whether it reinforced the rebels in their intransigence must now be moot.

The threat to Benghazi was the sole basis on which UN and Arab league support was obtained for a no-fly zone. The threat was averted within days. No further resolution was gained to support a Nato advance on Tripoli, let alone to kill Gaddafi from the air, because one would not have been forthcoming. The ambition to topple the regime was based on the claim to be "protecting civilians" by installing a more democratic one.

The claim that the intervention "saved thousands of lives" was thus wholly conjectural, and must be set against the thousands that have certainly been lost, and may yet be lost, through the intervention. These deaths can be justified only on the thesis that any precipitated revolution is worth any number of lives – as is asserted by apologists for Iraq.

There would be no foreign troops on the ground

This Nato pledge was mendacious. From the moment air power failed to achieve the undeclared goal of Tripoli's surrender, the pledge was broken. British ground troops were extensively deployed in Libya, the distinction between overt and covert forces being spurious. "Special" soldiers are still soldiers, and will shortly be releasing a flood of "how I captured Tripoli" memoirs. Close air support is also identical in tactical effect to ground artillery, as deployed in the final assault on the Gaddafi compound. Britain gave the rebels an air force – and can hardly withdraw it now.

Britain was not taking sides in a foreign civil war

This has been stated throughout, but it clearly was. The rescue of Benghazi mutated, as did the Iraq venture, into a wider war to remove a regime no longer to Britain's liking. Aid of every sort was given to the rebels, from political and diplomatic support to training, logistics and reportedly battlefield leadership in the attack on Tripoli.

Throughout the campaign, the British government has said it is "for the Libyan people to decide their own fate" and its involvement would end once a tyrant had departed the scene. That was naive. Britain has, with Nato, most emphatically decided the fate of the Libyan people. It has brought anarchy in the place of order, hoping that anarchy will be brief. It cannot disown the consequences.

The foreign secretary, William Hague, admitted as much this week. He declared: "We're not looking at British troops being a significant part of a stabilisation operation." We were told there would be no troops at all. But Britain cannot wreck someone else's country and then walk away from it. From the start of this operation David Cameron knew that if he toppled Gaddafi, he would own the place. It was no good constantly saying he would "learn from Iraq". The lesson of Iraq was, don't do it in the first place.